I worked for UHAUL back in '89-'90 as a Mobile Repair Unit. There were big trucks that had air compressors belt driven off the engine. IIRC they were for the air ride suspensions. Might keep an eye out for BIG ORANGE and WHITE trucks in the salvage yards?
There is a local guy here, he has TRAIN horns under his raised bed. When he pulls the chain you see thousands of people jerk, twist, jump, fall, cuss, and look around! Not gonna lie...I laughed until I cried !

In some parts of the country that will get you the attention you deserve.

All fun aside, I am interested in using my vacuum wipers also. I hope this sheds some light on the subject. My truck only had the drivers side wiper, so I will need to get the extra hardware for the other side, but that is a long way from priority at this point.

Hey guys, just wondering if any one knows proper amount of vacuum that the wipers require for a 55. Was hoping to purchase a little 12 volt vacuum pump to run them but not sure the volume per minute that would be correct for these.

Thanks

Don't know but even with a rebuilt vacuum motor, mine needed a well lubed linkage to successfully run two wipers.
Then you still have the issue with not wiping when you're on the throttle.
I fixed that deal with a Trico electro-vac, which is an electric vacuum pump that supplements the unsteady vacuum provided by the engine. Works like a charm. Provides enough vacuum to drag dry wipers across the windshield and places the wipers into the usable category when you're running down the road.

Rainex is good! My truck never had working vipers. Why should I all of a sudden feel I can't get by without them? I did send my wiper motor off to be rebuilt, however, and I do have a vacuum tank like the one Peter recommends. I'm getting soft and spoiled in old age.

The guy on ebay that has the trico pump for sale does not know what he has. Fuel injection??? Guess that is why it is $450. I paid $20. for one identical a couple years back that is available for the $20. price if anyone is interested.

Yikes! I saw a Trico Electro-Vac on e-bay for $450. I was all interested in your solution, but $450 certainly dampens my enthusiasm.

Jim

I paid $150 for it NOS on eBay in April 2017.
They do vary some in price. I've seen them from $80, all the way up. You can tell the NOS ones because they look 70 years old but have red plastic caps on the inlet and exhaust sides of the pump. They use Delco appliance motors too, which are very long lived for quality, so even a "used" one is
going to provide many years of service.

The guy on ebay that has the trico pump for sale does not know what he has. Fuel injection??? Guess that is why it is $450. I paid $20. for one identical a couple years back that is available for the $20. price if anyone is interested.

Yes, but I'd still need a pump to compress the air. Did you ever see the big Job engines that had a compressor sitting on top of the engine run by a belt off the crank?

I guess I'll give up on this thought. .... Unless I could fill said reservoir at home or at filling stations with an air compressor and blow my horns until I run out then fill it again. Sounds like fun.

Abe if you are set on using those air horns here's my solution. Use a 3 inch pvc pipe with threaded adaptors glued to each end for the reservoir. Maintain the needed air pressure with a 12 volt portable air compressor that has the digital auto setting. It will cycle to the preset psi when connected to a portable 12 volt power pack. The compressor comes with a threaded valve stem connector to hook to a Schrader on one end of the pvc. Plumb the other end to the valve and horns. Charge the power pack when needed. Reservoir could be mounted on frame with a remote fitting to get to where Compressor and battery pack would be accessible.

Seems like I read somewhere in the forum that electric wipers were optional on the larger trucks. Don't know if this is from '48 or if it started in '50 or what the exact deal was with the years.
I opted to go with the Trico electric vacuum pump as I had already had the vacuum wiper motor rebuilt...... and then I found out how restrictive the actual use of vacuum wipers was.
The vacuum pump actually makes (what in my opinion is a barely operational system) usable during real world driving.